The control of vehicular traffic often requires that certain lanes be closed to traffic and that traffic be temporarily be redirected to other lanes to accommodate variances in traffic flow, or as a result of repair work. It is also often necessary or desirable to control the ingress and egress of pedestrians in certain public areas, such as in amusement parks, college campuses, and tourist areas. This type of traffic control is often achieved by manually positioning freestanding markers, such as upright cones or drums, at desired locations and then removing or shifting same as necessary. This solution is time consuming, and in the situation where cones are placed directly on roadways to control or restrict vehicular traffic, poses a hazard to workers who must necessarily enter the roadway where vehicles are often traveling at high speeds.
As such, various pop-up traffic control devices have been developed which include a cartridge or housing embedded beneath the ground or roadway surface and a pylon or bollard which is housed within the below-ground cartridge when not in use. The pylon is remotely activated to raise same into an uppermost position for controlling or restricting traffic. A number of such traffic control devices are installed in side-by-side spaced relation with one another along a roadway or other area to provide traffic guidance. For the purpose of raising and lowering the pylon, many of these conventional devices include a rotatably driven threaded shaft which is mounted within the embedded lower cartridge. The shaft engages with a screw nut which is fixed to the pylon so that the nut and pylon traverse up or down on the shaft depending upon the rotational direction thereof. Examples of such an arrangement are disclosed in U.S. Pat. No. 5,425,595, and French Patent No. 2650-009.
The primary disadvantage of devices utilizing a screw-type mechanism to actuate the pylon is end-loading. More specifically, abrupt axial end-loading of the pylon occurs when the pylon is driven downwardly, for example by a vehicle tire, when the pylon is rising from the roadway surface. This downward driving of the pylon and nut often results in a stripped nut, or more significantly, the downward driving of the shaft itself which can cause damage to the motor and/or other internal components mounted within the lower area of the cartridge, such as the control board. These types of arrangements also include less than desirable sealing capabilities, which can result in the accumulation of dirt and grit on the threaded shaft and thus an abraded or damaged screw nut and/or shaft.
Other conventional pop-up traffic control devices utilize pneumatic devices to raise and lower the pylon. However, these arrangements often require close tolerances within their construction to prevent leakage, and involve increased costs associated with installation of appropriate pneumatic lines in the roadway.
With traffic control devices which are permanently installed in the roadway, exposure of the device to freezing temperatures can also present problems, such as ice formation adjacent the top of the cartridge which can restrict movement of the pylon. Conventional solutions to this problem included providing a heater disposed exteriorly of the pylon so as to heat the top cover or flange located adjacent the roadway surface to melt the ice. However, since the top cover is typically of significant width and thickness dimensions, a high-wattage heater and considerable warm-up time are necessary. In addition, angled road grades often create complications with existing devices, wherein the interference between the top flange or plate and the pylon can jam or stall the motor.
The present invention relates to a retractable-type barrier or pylon arrangement including an extendible and retractable pylon or cylinder which is actuated by a drive mechanism capable of compensating for an abrupt axial downward movement of the pylon, thus avoiding damage to the drive mechanism itself and/or other internal components of the system. The invention also incorporates an improved sealing arrangement which minimizes the amount of water and debris entering the arrangement from the surface, and an improved heating system which requires less energy.
More particularly, one aspect of the invention relates to a barrier arrangement including a generally tubular housing mounted within the ground so that an upper end thereof is generally flush with the ground surface. A post is disposed within the housing and is telescopingly movable relative thereto between an uppermost position wherein the post extends upwardly from the upper end of the housing and above the ground surface and a lowermost position wherein the post is disposed substantially completely within the housing and beneath the ground surface. A drive mechanism moves the post between the uppermost and lowermost positions, which drive mechanism includes a rotatable drive shaft having a smooth outer surface, and a block-like member disposed in clamping engagement with the smooth outer surface and non-movably fixed to the post. Rotation of the drive shaft causes displacement of the block-like member and the post relative to and along the drive shaft to move the post into one of the uppermost and lowermost positions.
Another aspect of the invention relates to a retractable pylon arrangement including a generally upright cartridge embedded within an opening in the ground so that an uppermost end thereof is substantially level with the ground surface. A pylon is disposed in a telescoping manner within the housing and is movable between an extended position wherein the pylon is cantilevered upwardly from the ground and a retracted position wherein the pylon is positioned within the cartridge and beneath the ground surface. A remotely-controlled drive mechanism moves the post between the extended and retracted positions, and an annular flange closes off the uppermost end of the cartridge. The flange has an inner terminal periphery disposed in surrounding relation with the pylon which defines an opening to permit movement of the pylon between the extended and retracted positions. A flexible annular seal member is mounted on the inner periphery of the flange and extends inwardly so as to maintain contact with an outer surface the pylon during movement thereof.
A further aspect of the invention relates to a pylon arrangement for controlling vehicular traffic including a generally hollow housing structure fixed within the ground in a generally upright manner, and an elongate pylon mounted for movement into the housing structure into a retracted storage position and for movement out of the housing structure into an extended position for controlling traffic. A heating unit is disposed within the pylon which when energized effectively heats an outer wall of the pylon and prevents seizure of the pylon due to ice build-up at least adjacent the ground surface.
Other objects and advantages of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.